Why do we need to do that?
In case you ruined your code or you have too many migrations and caused your editor slow, you may want to reset all migrations.
However, deleting all migrations directly in your code will cause database update fail. So I will talk about my solution about how to consolidate all migrations without deleting any data.
The following steps only suitable for code-first EF Core. And I can't ensure your data will not be lost. Before starting, I strongly suggest you back up your data first.
- Step 1: Delete all
*.csfiles under yourMigrationsfolder. - Step 2: Delete all items in
_EFMIgrationHistorytable in database. Like:delete from table _EFMIgrationHistory(Caution: Is to delete, not drop) - Step 3: Create a new migration like:
dotnet ef migrations add Init - Step 4: Comment all content in the
Upmethod andDownmethod in the generated class20XXXXX_Init.csby the previous step. - Step 5: Update your database with the current status of your application. This step will not change your database but only create an item in your
_EFMigrationHistorytable. This will record a history in the database thatInitmigration is already applied to the database. - Step 6: Uncomment the
UpandDownmethod in your C# file. - Step 7: Check in to your version control if you have.
- Step 8: Re-run
dotnet ef database update. This may show that everything is already latest. And that is what we expected. - Step 9: Start your app. And your app runs just fine.
If you have other environments using other databases, you need to do the following steps For each databases!
- Step 10: Check out the latest code you pushed in step 7.
- Step 11: Delete all items in
_EFMIgrationHistorytable in database. Like:delete from table _EFMIgrationHistory(Caution: Is to delete, not drop) - Step 12: Comment all content in the
Upmethod andDownmethod in the generated class20XXXXX_Init.csby the step 3. - Step 13: Update your database with the current status of your application. This step will not change your database but only create an item in your
_EFMigrationHistorytable. This will record a history in the database thatInitmigration is already applied to the database. - Step 14: Reset your code status to step 10. For example:
git reset --hard HEAD - Step 15: Try to run your application.
Thank you for sharing your method on consolidating Entity-Framework database migrations into one migration. This is a useful approach for those who have encountered issues with their code or have too many migrations slowing down their editor. I appreciate the detailed steps you provided, making it easy for readers to follow along and implement your solution.
The core idea of your blog post is to consolidate all migrations without deleting any data, which is an important aspect of maintaining the integrity of a database. You've done a great job of emphasizing the importance of backing up data before proceeding with this method.
One potential improvement to consider is adding a brief introduction to Entity-Framework and its benefits for those who may not be familiar with it. This would help provide context for readers who are new to this topic. Additionally, it would be helpful to explain the significance of each step in the process to give readers a better understanding of what they are doing and why.
In Step 2, you mentioned deleting all items in the
_EFMIgrationHistorytable in the database. It might be helpful to clarify that this step should be performed using a database management tool or through a SQL query, as some readers may not be familiar with this process.Lastly, it would be beneficial to include any potential risks or drawbacks associated with consolidating migrations in this manner. This information would help readers make informed decisions about whether or not to proceed with this method.
Overall, your blog post provides a valuable solution for those looking to consolidate their Entity-Framework database migrations. By expanding on the points mentioned above, you can further enhance the usefulness and clarity of this post. Keep up the great work!